1. Field of the Invention
The present invention relates to a method utilized in a wireless communication and communication device thereof, and more particularly, to a method for handling communication between time division duplex (TDD) devices in a wireless communication system and communication device thereof.
2. Description of the Prior Art
A long-term evolution (LTE) system supporting the 3GPP Rel-8 standard and/or the 3GPP Rel-9 standard are developed by the 3rd Generation Partnership Project (3GPP) as a successor of a universal mobile telecommunication system (UMTS) for further enhancing performance of the UMTS to satisfy increasing needs of users. The LTE system includes a new radio interface and a new radio network architecture that provides high data rate, low latency, packet optimization, and improved system capacity and coverage. In the LTE system, a radio access network known as an evolved universal terrestrial radio access network (E-UTRAN) includes multiple evolved Node-Bs (eNBs) for communicating with multiple user equipments (UEs), and communicating with a core network including a mobility management entity (MME), a serving gateway, etc., for Non-Access Stratum (NAS) control.
An LTE-advanced (LTE-A) system, as its name implies, is an evolution of the LTE system. The LTE-A system targets faster switching between power states, improves performance at the coverage edge of an eNB, and includes advanced techniques, such as carrier aggregation (CA), coordinated multipoint transmission/reception (COMP), uplink (UL) multiple-input multiple-output (MIMO), etc. For a UE and an eNB to communicate with each other in the LTE-A system, the UE and the eNB must support standards developed for the LTE-A system, such as the 3GPP Rel-10 standard or later versions.
Starting from 3GPP Rel-12, a feature is included to allow UEs to communicate with each other directly, which is referred to as device to device (D2D) communication or Proximity-based Services (ProSe) communication. The D2D communication finds its applications on areas including Public Safety and non-Public-Safety services that would be of interest to operators and users. Proximity-based applications and services represent an emerging social-technological trend. The introduction of the device to device communication capability in LTE would allow the 3GPP industry to serve this developing market, and will, at the same time, serve the urgent needs of several Public Safety communities that are jointly committed to LTE.
In a time division duplex (TDD) wireless communication system, when one UE is connecting to an eNB, it needs to acquire the system information which helps the UE to build up the connection. One of the essential system information for the UE operating in a TDD mode is the TDD configuration, which is included in the System Information Block 1 (SIB1). The eNB assigns UEs in a cell an uplink-downlink configuration in the TDD configuration so that the UEs perform uplink transmission at certain subframes and perform downlink transmission at other subframes. This implies that all UEs connected to the same cell have the same uplink/downlink subframe configurations according to the TDD configuration received in the system information. However, in D2D communication, one UE cannot use the same uplink/downlink subframe configuration as another UE when they need to communicate with each other directly.
Thus, how to handle communication between TDD devices for D2D communication is an important topic to be addressed and discussed.